The analysis of the output of a wind turbine involves knowing with exactitude the density of the air, the velocity and other characteristics of the fluid current which falls upon its rotor. However, the data concerning the velocity and characteristics of the wind falling upon the blades are impossible to measure with exactitude, so we have to work with various estimation methods to obtain the relationship between the power produced by the wind turbine and the wind falling on the blades.
The validity of the methods presented within a scientific context has not been proven in the case where the meteorological tower is located some distance from the wind turbines. Further, several meteorological towers are used to control the production of a relatively small number of wind turbines as 7 wind turbines.
The latest method developed for this task is that patented by MADE Tecnologías Renovables Patent No. ES2198212; Method for the control of production in electric wind turbines. Inventors: M. Sanz-Badía, F. J. Val, A. Llombart. This method has succeeded in detecting anomalies of some 2% if maintained during a period of at least 8 weeks, but suffers from a number of disadvantages such as:                It characterises the production of all the wind turbines in a wind farm via the velocity and wind direction data from a meteorological mast, which does not represent the wind actually falling on a wind turbine since the mast could be located some considerable distance from the machines.        It does not take into account the possible effects of the standard deviation in the wind speed or relative humidity.        It does not provide an estimate of the wind turbine output.        The division into sectors (depending on the direction) in a narrow and fixed form (each preferably 5°) means that many of the sectors cannot be characterised.        The maximum error which it has been possible to detect is some 2%.        The wind turbine characterisation process is not automatic.        
This invention is intended to resolve these issues.